预应力混凝土梁的抗力精细概率模型及可靠度分析  

REFINED PROBABILISTIC MODEL OF RESISTANCE AND RELIABILITY ANALYSIS FOR PRESTRESSED CONCRETE BEAM

作　　者：蒋友宝[1] 罗军[1] 廖国宇[2] 张建仁[1] 

机构地区：[1]长沙理工大学土木与建筑学院,长沙410004 [2]中铁四院集团南宁勘察设计院有限公司,南宁530003

出　　处：《工业建筑》2015年第10期69-73,共5页Industrial Construction

基　　金：国家重点基础研究发展计划资助项目(2015CB057705);长沙理工大学"青年英才"支持计划项目

摘　　要：鉴于GB 50068—2001《建筑结构可靠度设计统一标准》给出的混凝土梁抗力概率模型和设计分项系数值主要是针对普通混凝土梁构件,对预应力因素的影响考虑不够充分。针对此不足,采用Monte Carlo抽样方法并结合已有的承载力计算式和各种抗力因素的概率模型,得到不同预应力筋、钢筋配置量下混凝土梁的精细抗力概率模型。在此基础上,分析预应力混凝土梁设计可靠度随多个参数变化的规律。结果表明:预应力混凝土梁结构的设计可靠度均随预应力筋配置量的增加而有较大幅度增长,因此在抗震和非抗震两种组合情形下仅用普通混凝土梁的可靠指标来代表预应力混凝土梁的可靠性,均会低估其与设计目标的偏差。The probabilistic model of resistance and partial factors of concrete beam given in Unified Standard for Reliability Design of Building Structures （ GB 50068—2001 ） are mainly applicable to the common concrete beam, and it lacks full considerations of influences of prestress.To overcome this shortcoming, a refined probabilistic model of resistance was obtained under different amounts of reinforced steel and prestressing tendon, using the Monte Carlo sampling method, as well as combining with the current probabilistic models of all resistant factors and the capacity formulas in codes.Then, the influences of interesting parameters on reliability index were analyzed for prestressed concrete beam.The results showed that the corresponding design reliability indexes were increased largely with the increase of the amount of prestressed tendons, thus the differences from the target ones were underestimated for both seismic combination and non-seismic combination if they were represented by the reliability indexes of the common concrete beam only.

关 键 词：预应力混凝土梁 MONTE Carlo抽样 抗力 精细概率模型 可靠度 配筋率 荷载效应比 

分 类 号：TU378.2[建筑科学—结构工程]